Over history, surveyors have used a variety of objects, such as rocks, blocks of stone, steel reinforcing bars, scrap metal, and poured concrete as reference points in their work of locating the boundary lines of land. Since it is highly desired that survey markers be permanent, blocks of cut stone have traditionally found favor; however, the use of stone blocks as survey monuments becomes obviously impractical where surveying is being conducted in remote areas not easily accessible by trucks and other vehicles.
A particular type of survey monument which has been used increasingly in surveying, particularly in remote areas, is shown in the prior U.S. patent to Berntsen, et al, U.S. Pat. No. 4,087,945. This patent shows a plurality of cylindrical aluminum rod sections which are added together one by one as the rod series is driven into the ground. Such multi-section survey markers have become popular because they are relatively light and can be carried to remote locations without undue burden, because they are essentially permanent, and because they can be driven deep into the ground to resist withdrawal or accidental dislodging, even in such unstable earth environments as the Alaskan tundra where the permafrost tends to throw off (during the alternate heating and cooling of the permafrost) objects which are not buried or embedded below the frost line. Sections of rod can easily be added to the multisection monument as it is driven into the ground so that the point of the monument can reach below the permafrost.
A problem is commonly encountered in modern surveying as it probably was in an antiquity: boundary monuments are often vandalized so that the location of a boundary line is lost, or the boundary marker is deliberately moved after it has been set by the surveyor. Any kind of survey monument is vulnerable to being deliberately moved, even a heavy stone block; the type of driven-type survey monument shown in U.S. Pat. No. 4,087,945 is less vulnerable to being moved because it is generally driven too far in the ground to be pulled out, but it still may be tampered with by unscrewing the top rod section and pulling it from the ground to destroy the evidence of the location of the survey marker.